58 research outputs found

    Azimuthal Charged-Particle Correlations and Possible Local Strong Parity Violation

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    Parity-odd domains, corresponding to nontrivial topological solutions of the QCD vacuum, might be created during relativistic heavy-ion collisions. These domains are predicted to lead to charge separation of quarks along the system’s orbital momentum axis. We investigate a three-particle azimuthal correlator which is a P even observable, but directly sensitive to the charge separation effect. We report measurements of charged hadrons near center-of-mass rapidity with this observable in Au+Au and Cu+Cu collisions at √sNN=200  GeV using the STAR detector. A signal consistent with several expectations from the theory is detected. We discuss possible contributions from other effects that are not related to parity violation

    Jet modification via π 0 -hadron correlations in Au+Au collisions at √sNN = 200 GeV

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    High-momentum two-particle correlations are a useful tool for studying jet-quenching effects in the quark-gluon plasma. Angular correlations between neutral-pion triggers and charged hadrons with transverse momenta in the range 4–12 GeV/c and 0.5–7 GeV/c, respectively, have been measured by the PHENIX experiment in 2014 for Au+Au collisions at √sNN = 200 GeV. Suppression is observed in the yield of high-momentum jet fragments opposite the trigger particle, which indicates jet suppression stemming from in-medium partonic energy loss, while enhancement is observed for low-momentum particles. The ratio and differences between the yield in Au+Au collisions and p+p collisions, IAA and ∆AA, as a function of the trigger-hadron azimuthal separation, ∆ϕ, are measured for the first time at the Relativistic Heavy Ion Collider. These results better quantify how the yield of low-pT associated hadrons is enhanced at wide angle, which is crucial for studying energy loss as well as medium-response effects

    Systematic study of nuclear effects in p+Al, p+Au, d+Au, and 3He+Au collisions at √sNN = 200 GeV using π 0 production

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    The PHENIX collaboration presents a systematic study of inclusive π 0 production from p+p, p+Al, p+Au, d+Au, and 3He+Au collisions at √sNN = 200 GeV. Measurements were performed with different centrality selections as well as the total inelastic, 0%–100%, selection for all collision systems. For 0%–100% collisions, the nuclear-modification factors, RxA, are consistent with unity for pT above 8 GeV/c, but exhibit an enhancement in peripheral collisions and a suppression in central collisions. The enhancement and suppression characteristics are similar for all systems for the same centrality class. It is shown that for high-pT -π 0 production, the nucleons in the d and 3He interact mostly independently with the Au nucleus and that the counter intuitive centrality dependence is likely due to a physical correlation between multiplicity and the presence of a hard scattering process. These observations disfavor models where parton energy loss has a significant contribution to nuclear modifications in small systems. Nuclear modifications at lower pT resemble the Cronin effect – an increase followed by a peak in central or inelastic collisions and a plateau in peripheral collisions. The peak height has a characteristic ordering by system size as p+Au > d+Au > 3He+Au > p+Al. For collisions with Au ions, current calculations based on initial state cold nuclear matter effects result in the opposite order, suggesting the presence of other contributions to nuclear modifications, in particular at lower pT

    清涼飮料税論

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    The production of J/\).psi\) and ψ(2S)\psi(2S) was measured with the ALICE detector in Pb-Pb collisions at the LHC. The measurement was performed at forward rapidity 2.5 < y < 4 \() down to zero transverse momentum \(p_{\rm T} in the dimuon decay channel. Inclusive J/\).psi\) yields were extracted in different centrality classes and the centrality dependence of the average pTp_{\rm T} is presented. The J/\).psi\) suppression, quantified with the nuclear modification factor RAAR_{\rm AA} , was studied as a function of centrality, transverse momentum and rapidity. Comparisons with similar measurements at lower collision energy and theoretical models indicate that the J/\).psi\) production is the result of an interplay between color screening and recombination mechanisms in a deconfined partonic medium, or at its hadronization. Results on the ψ(2S)\psi(2S) suppression are provided via the ratio of ψ(2S)\psi(2S) over J/\).psi\) measured in pp and Pb-Pb collisions

    Use of Therapeutic Neuroscience Education to address psychosocial factors associated with acute low back pain: a case report

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    Acute low back pain (LBP) from injuries is prevalent in the work place. It has been shown that patients with psychosocial factors often progress with persistent pain and lead to significant workers compensation costs. Therapeutic Neuroscience Education (TNE) has been shown to be beneficial in changing a patient\u27s cognition regarding their pain state, which may result in decrease fear, anxiety and catastrophization. A 19-year-old female who developed LBP from a work injury was the patient for this case report. A physical examination, Numeric Pain Rating Scale (NRPS), Oswestry Disability Index (ODI), Fear-Avoidance Beliefs Questionnaire (FABQ), Keele STarT Back Screening Tool (Keele SBST) and Acute Low Back Pain Screening (ALBPS) Questionnaires were assessed during initial physical therapy visit and discharge. Treatment consisted of use of TNE, manual therapy and exercises. She attended five total visits over a 2-week period prior to full discharge. During the initial visit the patient reported NRPS = 3/10, ODI = 36%, FABQ-PA = 23, FABQ-W = 30, Keele SBST = 4/9, ALBPS = 101. At discharge the patient reported a 0 on all outcome questionnaires with ability to return to full work and no pain complaints
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